Methods and systems for full-color three-dimensional image display

ABSTRACT

Methods and systems for displaying full-color three-dimensional imagery are provided. A first color set, having a first color spectrum, is defined to include a first set of LEDs. The first color set is assigned to a first color-coded image perspective. A second color set, having a second color spectrum, is defined to include a second set of LEDs. The second color set is assigned to a second color-coded image perspective. The full-color three-dimensional imagery is caused by activating, alternatively, at least two LEDs of the first color set or the second color set and one LED of a remaining color set and displaying the three-dimensional image based on the first image perspective and the second image perspective.

Cross-Reference to Related Applications

This application is a continuation of U.S. patent application Ser. No.14/255,591, filed Apr. 17, 2014, now U.S. Pat. No. 9,507,167, which is acontinuation-in-part of U.S. patent application Ser. No. 13/459,939,filed Apr. 30, 2012, now U.S. Pat. No. 8,704,845, which is acontinuation of U.S. patent application Ser. No. 12/243,704, filed Oct.1, 2008, now U.S. Pat. No. 8,169,445, which claims the benefit ofpriority of U.S. Provisional Application No. 60/976,794, filed Oct. 1,2007, entitled “Full Color Anaglyph 3D Monitor,” the disclosure of whichis expressly incorporated herein by reference in its entirety.

BACKGROUND Technical Field

Embodiments consistent with the presently-claimed invention are relatedto display systems and, in particular, to systems for displayingfull-color anaglyph three-dimensional imagery without a loss intwo-dimensional display quality.

Discussion of Related Art

Three-dimensional display systems have gained increasing popularity due,in part, to advances in image processing and display technology. Some ofthese advances have been applied in a variety of applications, includingvirtual reality flight simulators, automotive design, oil and gasexploration, and image-guided surgical procedures.

One common three-dimensional display technology is a stereoscopicdisplay. Stereoscopic displays may use any one of several methods togenerate a three-dimensional image by presenting a viewer with differentperspectives of a common image. For example, many of the methods codeand decode at least two different perspectives of a common image usingat least two separate optical channels. Coding and decoding methods maybe based on color, polarization, spatial separation, or time. The codedimages are often similar, but offset with respect to one another. Whenviewed by a user, the disparity in the images is interpreted by thebrain as depth.

An anaglyph, for example, is stereoscopic display method that uses colorto code and decode separate image perspectives. Using color, an anaglyphmethod codes and decodes the image perspective based on one or morewavelengths corresponding to a portion of the visible light spectrum.The color-coded images are presented to a viewer wearing appropriatelycolor filtered glasses. In operation, left-image data may be placed inan optical channel corresponding to the color red in the visible lightspectrum. Similarly, right-eye image data may be placed in anotheroptical channel corresponding to the colors green and blue in thevisible light spectrum. Each image is offset with respect to each other,producing a depth effect. The brain integrates the two color-codedimages, creating a three-dimensional image.

In certain situations, however, three-dimensional display systems usinganaglyphs may cause visual discomfort. In some cases, visual discomfortmay result from each eye receiving a separate limited color spectrum asdescribed above. Other stereoscopic methods may provide improved colorrepresentation. For example, some methods use multiple projectors withcomplementary polarizers to produce three-dimensional imagery. Many ofthese methods, however, suffer from other undesirable effects, includingflicker, reduced brightness, and optical cross talk. Furthermore, manyof these alternative methods are considerably more expensive thananaglyph methods.

Further drawbacks of three-dimensional display systems using anaglyphsare compromised resolution, brightness, and viewing angle whendisplaying two-dimensional images. That is, when watching traditionaltwo-dimensional video content through a three-dimensional anaglyphdisplay, or when watching three-dimensional video content in 2D mode.

SUMMARY

Methods and systems for displaying full-color three-dimensional imageryare provided. A first color set, having a first color spectrum, isdefined to include a first set of LEDs. The first color set is assignedto a first color-coded image perspective. A second color set, having asecond color spectrum, is defined to include a second set of LEDs. Thesecond color set is assigned to a second color-coded image perspective.The full-color three-dimensional imagery is caused by activating,alternatively, at least two LEDs of the first color set or the secondcolor set and one LED of a remaining color set and displaying thethree-dimensional image based on the first image perspective and thesecond image perspective.

In some embodiments, both color sets may be produced by one broadbandillumination system or set of LEDs. The resulting broadband light sourcemay be separated into two color sets by an array of filters that operateon the light emanating from the pixels on a pixel, row, or column basis.

In some embodiments, the first color spectrum includes wavelengthscorresponding to each of a first red LED, a first green LED, and a firstblue LED.

In certain embodiments, the second color spectrum includes wavelengthscorresponding to each of a second red LED, a second green LED, and asecond blue LED.

In certain embodiments, the first color spectrum is different from thesecond color spectrum. The first color-coded image perspective and thesecond color-coded image perspective may correspond to one of aright-eye image and a left-eye image.

In certain embodiments, the at least two LEDs of the first color set orthe second color set include a red LED and a blue LED, and the one LEDof the remaining color set is a green LED.

In some embodiments, a multi-spectral imagery is displayed that includesthermal, infrared, or acoustic imagery coded using single wavelength

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention. Further embodiments andaspects of the presently-claimed invention are described with referenceto the accompanying drawings, which are incorporated in and constitute apart of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram illustrating an exemplary system forproviding a full-color three-dimensional display.

FIG. 2 illustrates a graph of the spectral transmission characteristicsof exemplary color sets.

FIG. 3 shows a block diagram of exemplary color filter panels.

FIGS. 4A, 4B, 4C, and 4D show additional block diagrams of exemplarycolor filter panels and graphs of the respective spectral transmissioncharacteristics of filter elements included in the panels.

FIG. 5 shows a flowchart illustrating steps in an exemplary method fordisplaying full-color three-dimensional imagery.

FIG. 6 shows a flowchart illustrating steps in an additional exemplarymethod for displaying full-color three-dimensional imagery.

FIG. 7 shows a block diagram illustrating an exemplary system forproviding a full-color two-dimensional or three-dimensional display.

FIG. 8 illustrates a graph of the spectral transmission characteristicsof exemplary color sets.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments, examples ofwhich are illustrated in the accompanying drawings. Wherever possible,the same reference numbers will be used throughout the drawings to referto the same or like parts.

FIG. 1 shows a block diagram illustrating exemplary full-colorthree-dimensional display system 100. In some embodiments, displaysystem 100 may be associated with a media display system, anentertainment display system, a television, a desktop or mobilecomputer, a digital still or a digital video camera, a personal mediaplayer, a mobile phone, or like device. In other embodiments, displaysystem may be a component of a virtual reality system, an engineeringdesign system, a medical device, or other like device.

As shown in FIG. 1, system 100 may include, among other features,display device 110 and viewing device 180. Display device 110 mayinclude, among other features, backlight 120, light guide 130, color ormonochrome liquid crystal display (LCD) panel 140, color filter panel150, bus 160, and controller 170. Viewing device 180 may include, amongother features, right eye filter 180-A and left eye filter 180-B witheach filter having a bandpass that matches a different one of the colorset outputs provided by color panel 150.

In certain embodiments, display device 110 may be adapted to outputinformation coded as full-color anaglyph three-dimensional imagery or asstandard two dimensional imagery. Information may include one or acombination of images, text, video, or the like. In some embodiments,display device 110 may output imagery using, among other components, oneor a combination of flat panel technologies, such as plasma, liquidcrystal and light-emitting diode. In certain embodiments, display device110 may also output imagery using, among other components, micro displaytechnologies, such as Liquid Crystal on Silicon (LCoS), electro-opticmodulators, and micro-electromechanical systems. For example, displaydevice 110 may be a liquid crystal display (LCD) as illustrated inFIG. 1. In other examples, display device 110 may be a system thatincludes a projector and a screen wherein the color panel is in theprojector. Display device 110 may be used in conjunction with viewingdevice 180 adapted to view imagery generated by display device 110.

Backlight 120 may be a light source configured to output one or morecoded image perspectives of a three-dimensional image. For example,backlight 120 may be configured to utilize anyone of several colormodels sufficient to reproduce a color spectrum to support full-coloranaglyph three-dimensional imagery or pseudo color multi-spectral imagefusion. For example, the light source may consist of florescent, LED,arc lamp, laser, or any other sources which may be configured to outputthe required wavelengths of light as determined by the design of colorfilter panel 150. In some embodiments, backlight 120 may be adapted touse an additive color model, such as RGB. Using the RGB color model,varying intensities and bandwidths of a red, a green, and a blue lightsources may be combined to produce a broad color spectrum. Backlight 120may include a red LED, a green LED, and a blue LED. In otherembodiments, backlight 120 may be adapted to utilize alternative colormodels, such as a four color space or a six color space model.Accordingly, in some embodiments, backlight 120 may include one or acombination of differently colored LEDs, including combinations ofgreater than and less than three colors.

In some embodiments, backlight 120 may include LEDs grouped as a colorset, each color set configured to produce a particular color spectrum.The color spectrum of the color set may correspond to a portion of thevisible light spectrum used to code an individual image perspective(left or right) of a three-dimensional image. That is, one set of LEDscorresponding to a color set may be configured to display only one ofthe two image perspectives. Similarly, the remaining set of LEDscorresponding to another color set may be configured to only display theother image perspective. An individual image perspective may beassociated with either a left-eye image or a right-eye image. Right eyefilter 180-A and left eye filter 180-B may be configured to receiveimage data on separate optical channels differentiate based onwavelengths corresponding to each color set. For example, one opticalchannel may be configured to carry information coded based on left-eyeimage perspective and the other optical channel may be configured tocarry information coded based on the right-eye image perspective. Thatis, each color set may be associated with an optical channel to transmitand receive a particular image perspective.

In some embodiments, the transmission range of the color set may bedetermined based on the wavelengths associated with the LEDs comprisingthe color set. For example, backlight 120 may include a first color setcomprised of red LED R₁, green LED G₁, and blue LED B₁. Backlight 120may also include a second color set comprised of red LED R₂, green G₂,and blue LED B₂, each LED having a different wavelength compared thecorresponding LED in the first color set. Thus, a first color set maycorrespond to color spectrum, or color space, used to code either aright-eye or left-eye image perspective of three-dimensional image.Similarly, the second color set may correspond to the remaining imageperspective. In some embodiments, backlight 120 may include other colorsets with at least one red LED, one green LED, and one blue LED. Forexample, a first color set may include red LED R₁, green LED G₂, andblue LED B₁. Similarly, a second color set may include red LED R₂, greenLED G₁, and blue LED B₂.

A particular color space reproduced using a corresponding color set maybe a subset of the visible light spectrum. That is, colors used to codeand to display a particular image perspective may be reproduced to theextent that those colors are reproducible using the combination ofcolors included in the corresponding color set in backlight 120. Incertain embodiments, backlight 120 may comprise color sets that includefour or greater distinct LED colors in each color set to increase thereproducible subset of the visible light spectrum. For example, onecolor set may include, in addition to a red, green, and blue LED, a cyanLED. The complementary color set may include the same color LEDs, yeteach color may differ slightly in wavelength as previously discussed.Alternatively, the complementary color set may contain base color LEDs,red, green, and blue, adding a yellow LED.

In some applications, additional color LEDs, beyond the base color red,green, and blue LEDs, may be used to display multi-spectral imagery on asingle display panel. For example, a right-eye image perspective may becoded using a red, a green, and a blue LED from a first color set.Similarly, a left-eye image perspective may be coded using differentred, green, and blue LEDs from a complementary color set. A yellow LEDassociated with either the first color or the second color set may becoded to display pseudo color spectral imagery, such as thermal imagery,separately or in combination with the right and the left imageperspectives. Pseudo color spectral imagery may be displayed in varyinghues, or shades, of a single color. For example, a pixel coded witheight bits of information can represent a larger range of colors than arepresentation in the same color space that uses six bits ofinformation. Accordingly, a single color may be reproduced in varyingshades based on the associated pixel resolution.

Light guide 130 may include an optical component adapted to evenlydistribute light from backlight 120 across LCD panel 140. For example,light guide 130 may be optically coupled to backlight 120 using one or acombination of a mixing light guide (not shown) and a mirror (notshown). Light guide 130 may be composed of glass, acrylic, or otherpolymethacrylate material, suitable to couple light from backlight 120to LCD panel 140. Light guide 130 may include an extraction pattern onone surface adapted to provide uniform coupling of light output frombacklight 120 to LCD panel 140. The extraction pattern may be createdusing several methods, including but not limited to, screen printing andinjection molding.

Liquid crystal display (LCD) panel 140 may include an array of liquidcrystal light valves associated with one of several picture elements, orpixels, forming the display. LCD panel 140 may be coupled to receivelight from backlight 120 through light guide 130. Each liquid crystallight valve may be coupled to transmit light from backlight 120 throughcolor filter panel 150. In some embodiments, a light valve may beconfigured as a layered structure that includes a pair of complementarypolarizers, a liquid crystal, and a pair of glass plates. One glassplate may be covered by a transparent electrode and the other coated toprovide the electronics, such as thin film transistors (TFT)s, necessaryto address and drive the individual pixels. Each liquid crystal lightvalve may be individually addressable by controller 170 to vary theamount of light emanating from the pixel in response to applying avoltage across the electrodes. In some embodiments, each pixel may besubdivided into sub pixels or unit pixels, each associated with anindividual liquid crystal light valve. A sub pixel may be coated with acolor filter to pass a particular wavelength and to reflect or absorbother wavelengths.

Color filter panel 150 may include an array of colored filter elementsadapted to transform light output by backlight 120 into colored light ofa particular pair-wise set of wavelengths. In some embodiments, aparticular colored filter element may be common, to both pair-wise setsof wavelengths for a particular color. For example, a common red coloredfilter element may transmit different red wavelengths from differentcolor sets. In other embodiments, a particular colored filter elementmay be coded to transmit wavelengths associated only with a particularcolor set. For example, a first red colored filter element may transmita first red wavelength associated with a red LED from a first color set,but reflect a second red wavelength associated with a red LED from asecond color set. Similarly, a second red colored filter element maytransmit a second red wavelength associated with a red LED from a secondcolor set, but reflect a first red wavelength associated with a red LEDfrom a first color set.

In some embodiments, color filter panel 150 may be coupled to LCD panel140 using a sealant and one or more spacers to maintain sufficientspacing between color filter panel 150 and LCD panel 140. In someembodiments, color filter panel 150 may be composed of a glass substratecoated with dyes, pigments, or metal oxides to form individual coloredfilters. In other embodiments, the color filters may be a coating on anexisting substrate on LCD panel 140. Each colored filter may be arrangedin one of several patterns based on the arrangement of the correspondingpixels on LCD panel 140 as illustrated in FIG. 3. In certainembodiments, the color filters may be arranged in a random pattern (notshown) or a pseudo-random pattern (not shown) to provide secured viewingof display system 100. That is, by arranging the color filters in arandom pattern, a displayed image may appear unrecognizable or scrambledto viewers not wearing viewing device 180.

In certain embodiments, color filter panel 150 may be comprised of stripfilters arranged horizontally or vertically over each row or column ofpixels on LCD panel 140. Unlike individual color filter elementspreviously discussed, complementary strip filter element may be adaptedto transmit all wavelengths from one color set and to reflect or absorbthe wavelengths from the remaining color set. Complementary strip filterelements may be placed adjacent to each other in a repeated patternacross color filter panel 150. Strip filter elements may be composed ofmultiple metal-organic layers configured to create a particular passband.

Viewing device 180 may include one or more devices configured to enablea user to view full-color anaglyph three-dimensional imagery. Viewingdevice 180 may be a complete viewing device or a component of a viewingsystem. For example, viewing device 180 may include stereoscopic glasseswith individualized filters separating left and right imageperspectives. In some embodiments, each individualized filter may beadapted to receive and transfer to each eye of a user a specific set ofwavelengths. In some embodiments, each individualized filter may be amulti-bandpass filter configured to receive a particular set ofwavelength intervals grouped into a color set. For example, right-eyefilter 180-A may be configured to receive and transfer wavelengths of afirst color set associated with a right-eye image perspective.Wavelengths of a first color set may include red at 629 nm, green at 532nm, and blue at 466 nm. Left-eye filter 180-B may be configured toreceive and transfer a complementary set of wavelengths associated witha left-eye image perspective. Wavelengths of a second color set mayinclude red at 615 nm, green at 518 nm, and blue at 432 nm.

Controller 170 may be one or more processing devices configured toexecute processor readable instructions to perform functions associatedwith display device 110. For example, controller 170 may be a processor,application specific integrated circuit (ASIC), microcontroller, fieldprogrammable gate array (FPGA), or like device capable of executingprocessor readable instructions. In some embodiments, controller 170 maybe coupled to communicate with backlight 120, LCD panel 140, and colorfilter panel 150 using bus 160. Bus 160 may include an optical orelectrical communication channel configured to transfer data betweenbacklight 120, LCD panel 140, color filter panel 150, and controller170. In some embodiments, data may include display data received from anexternal source (not shown).

FIG. 2 illustrates graph 200 of the spectral transmission of exemplarycolor sets. As shown in FIG. 2, color set A may represent a first set ofspectral peaks 210 of LEDs associated with a first color set ofbacklight 120. For example, a first blue LED may have a spectral peak of466 nm 210-A. A first green LED may have a spectral peak of 532 nm210-B. A first red LED may have a spectral peak of 629 nm. Color set Bmay represent a second color set of spectral peaks 220 of LEDsassociated with a second color set of backlight 120. For example, asecond blue LED may have a spectral peak of 432 nm 220-A. A second greenLED may have a spectral peak of 518 nm 220-B. A second red LED may havea spectral peak of 615 nm. As shown in combined spectral transmissiongraph 230, color set A and color B may represent separate opticalchannels of common colors shifted in wavelength.

FIG. 3 shows a block diagram of an exemplary color filter panel 150. Asshown in FIG. 3 and previously discussed, color filter panel 150 mayinclude an array of individual color filter arranged in a particularpattern. In some embodiments, the pattern may be stripe pattern 310,mosaic patter 320, delta pattern 330, or other pattern. Each row of eachpattern may be associated with a corresponding row of pixels or subpixels of LCD panel 140. In some embodiments, each row may containindividual color filter elements each adapted to pass one or morewavelengths associated with a particular color set. For example, row310-A may include a red color filter element R adapted to pass awavelength associated with a first red LED, a second wavelengthassociated with a second red LED, or wavelengths associated with thefirst and the second red LEDs. In some embodiments, color filter panel150 may include color filter elements adapted to pass one wavelength ofa particular color on a first row and a different wavelength of the samecolor on a adjacent row. For example, row 320 A may include a blue colorfilter element B₁ configured to pass a first wavelength associated witha first blue LED, while reflecting or absorbing a second wavelengthassociated with a second blue LED. Similarly, row 320 B may include adifferent blue color filter element B₂ configured to pass a secondwavelength associated with a second blue LED, while reflecting orabsorbing a first wavelength associated with a first blue LED. In otherwords, color filter panel 150 may be configured to interlacecomplementary wavelength pairs of a common color. Color filter elementpairs R₁ and R₂ and G₁ and G₂ located in rows 320-A, 320-B, 320-C,330-A, 330-B, and 330-C may be configured to operate in a similar mannerto color filter element pairs B₁ and B₂. In some embodiments, colorfilter elements associated with a particular color set may be arrangedon a single row or across multiple rows.

FIGS. 4A, 4B, 4C, and 4D show additional block diagrams of exemplarycolor filter panel 150 and graphs of the respective spectraltransmission characteristics of the filter elements. In certainembodiments, color filter panel 150 may include a repeating pair ofstrip filter elements arranged horizontally or vertically across colorfilter panel 150. For example, in FIG. 4A, strip filter_A 410 and stripfilter_B 420 are arranged vertically in an alternating manner. That is,strip filter_A 410 and strip filter_B 420 are placed in adjacent columnsacross color filter panel 150 corresponding to columns 1 through n ofLCD panel 140. In other embodiments, as shown in FIG. 4B, strip filter_A410 and strip filter_B 420 may be arranged horizontally and placed inadjacent rows across color filter panel 150 corresponding to rows 1through n LCD panel 140. Each strip filter element may be adapted totransmit wavelengths from one color set and to reflect or absorb thewavelengths from the remaining color set. For example, as shown in FIG.4C, strip filter_A 410 may include a filter that passes a first colorset, which includes wavelengths centered at 432 nm, 518 nm, and 615 nm,while reflecting or absorbing other wavelengths. Complementary stripfilter_B 420, as shown in FIG. 4D, may be adapted to pass wavelengthscentered at 466 nm, 532 nm, and 628 nm, while reflecting or absorbingother wavelengths. Accordingly, a repeated pattern of strip filter_A 410placed adjacent to strip filter_B 420, organized in rows or columns, maycover all pixels on LCD panel 140 with alternating rows or columns of afirst color set and a second color set.

FIG. 5 shows a flowchart illustrating steps in an exemplary method fordisplaying full-color three-dimensional imagery. It will be readilyappreciated by one having ordinary skill in the art that the illustratedprocedure can be altered to delete steps, move steps, or further includeadditional steps.

In step 510, a first color set is defined to include a plurality ofLEDs. In some embodiments, the first color set may have a particularcolor spectrum corresponding to one of two image perspectives of acommon multi-dimensional (typically 3D) image. Each image perspectivemay be color-coded using a particular color spectrum. For example, aright-eye image perspective may be color-coded with a color spectrumidentified by a set of wavelengths corresponding to a set of colors usedto code the image perspective. In some embodiments, the color sets mayinclude pairs of red LEDs, pairs of green LEDs, and pairs of blue LEDs.In other embodiments, the color set may include greater or fewer pairsof LEDs, or other color combinations sufficient to reproduce thecolor-coded image perspective. For example, other color combinations mayinclude red, yellow, green, cyan and blue LEDs. In step 510 a firstcolor set is chosen, such that each LED has distinct spectralcharacteristics corresponding to spectral characteristics of the viewingdevice 180.

In step 520, a second color set is defined to include a plurality ofLEDs with spectral characteristics distinct from the first color set asdescribed in step 510. Accordingly, the second color set may have aparticular color spectrum corresponding to a different imageperspective. For example, a right-eye image perspective may becolor-coded with a color spectrum associated with the first color set. Aleft-eye image perspective may be color-coded with a different colorspectrum associated with a second color set. In some embodiments, thesecond color set may include a red LED, a green LED, and a blue LED. Inother embodiments, the color set may include greater or fewer LEDs, orother color combinations sufficient to reproduce the color-coded imageperspective. For example, other color combinations may include a red, ayellow, a green, and a blue LED. Each LED of the second color set mayhave distinct spectral characteristics as compared to each correspondingLED of the first color set. For example, the first color set may includea blue LED having a spectral peak of 466 nm, a green LED having aspectral peak of 532 nm, and a red LED having a spectral peak of 629 nm.The second color set may include a LEDs of corresponding to the samecolors, having wavelengths of 432 nm, 518 nm, and 615 nm, respectively.

In step 530, each color-coded image perspective may be displayed byalternatively activating LEDs corresponding to an associated color set.For example, a right image-eye image perspective, associated with afirst color set, may be displayed by activating only LEDs assigned tothe first color set. Similarly, a left-eye image perspective, associatedwith a second color set, as previously described, may be displayed byactivating only LEDs assigned to the second color set. In someembodiments, each color-coded image perspective may be displayed at arate equal to one half of a frame rate. In some embodiments, includingapplications displaying a fusion of multi-spectral data on a singledisplay, LEDs within one or multiple color sets may be activated one ata time. For example, certain types of spectral imagery, such as thermalimagery, may be coded using a single color or wavelength. Similarly,other spectral sources, such infrared imagery may be coded using anothercolor. Imagery from one image source may be displayed by illuminatingthe corresponding LED is illuminated. Imagery from additional sourcescoded with a single LED may be displayed sequentially. In this mannermany sources may be displayed during a single frame time. The dwell timeof the pseudo color multi-spectral images would not be required to beequal between the images. In some embodiments, a single LED used to codespectral imagery for may be configured to produce a range of hues basedon the pixel resolution determined by one or a combination of thecontroller and the backlight. For example, a yellow LED may be coded as8-bits, thereby providing 256 possible hues of yellow. Pseudo colormulti-spectral imagery coded using a single LED may also appear asstereoscopic imagery along with other three-dimensional imagery on asingle display. For example, processing techniques may use common edgesbetween visual stereoscopic imagery and multi-spectral imagery to createa parallax.

In some embodiments, a portion of each color-coded image may be displaysimultaneously. Displaying a portion of each image perspective mayreduce visual discomfort experienced by a viewer resulting from adisplay switching between right-eye and left-eye image perspectives. Insome embodiments, at least two LEDs of the first color set or the secondcolor set and one LED of a different color set are activated together,while deactivating the remaining LEDs. For example, a portion of aright-eye image perspective may be displayed using a blue LED and a redLED associated with a first color set. Simultaneously, a portion of theleft-eye image perspective may be displayed using a green LED. Duringthe next display cycle, the remaining portions of the right-eye imageand left-eye image perspectives may be displayed in a similar manner.Accordingly, both eyes of the viewer receive some light at all times,reducing the effects of switching characterized as flicker.

FIG. 6 shows a flowchart illustrating steps in an additional exemplarymethod for displaying full-color three-dimensional imagery. It will bereadily appreciated by one having ordinary skill in the art that theillustrated procedure can be altered to delete steps, move steps, orfurther include additional steps. Steps 610 and 620 include elementssimilar to those described in steps 510 and 520 respectively.

In step 630, a first color-coded image perspective is displayed oneither the odd or the even rows or columns of a display in an interlacedmanner. In other words, a particular color-coded image perspective,associated with one of a left-eye or right-eye image, may be displayedon either of the odd or the even rows or columns of a display. Theremaining image perspective may be displayed simultaneously on theremaining rows or columns.

In some embodiments, separating each individual color-coded imageperspective may be performed using rows of color filters coupled to eachrow of the display. In some embodiments, a row of color filters mayinclude individual color filter elements, arranged in one of severalpatterns, such as those illustrated in FIG. 3. Each color filter elementmay have transmission characteristics suitable to pass a wavelengthassociated with one component of the particular color set and reflectiveand/or absorptive characteristics that prevent the transmission of otherwavelengths. For example, a row of color filters, having a colorspectrum associated with a first color set, may be coupled to each oddrow of the display. The row may contain only color filter elementscorresponding to the wavelengths associated with a first color set.Accordingly, only imagery coded with wavelengths associated with thefirst color set may be displayed on the odd rows of the display. In someembodiments, a row of color filters may include at least one colorfilter element associated with a different color set than the othercolor filter elements. For example, a row of color filters may include agreen color filter element associated with a second color set and redand blue color filter elements associated with a first color set. Thecolor filters may be arranged in tiling patterns as shown in FIG. 3,pattern 310, 320, or 330, or in an interleaved or pseudo random fashionas described above. An interleaved or pseudo random pattern enhancesresolution by creating overlapping white pixels—for example, nonadjacentRGB LEDs—that are integrated by the human eye. Ultimate resolution isachieved when one pixel location is used to sequentially display R1, G1,B1, G2, B2, R2 in two-dimensional mode. The precise sequence may beordered to reduce flicker or other artifacts. For example, a randomizedorder that changes the timing between G1 and G2, which are the brightestcolors as perceived by the human eye, will render flicker undetectable.

In other embodiments, separating each individual color-coded imageperspective may be performed using strip filters as described in FIG. 4.The strip filters consists of a pattern of alternating rows or columnsof spectrally distinct filter elements. That is, each strip filterelement may transmit wavelengths from one color set and reflect orabsorb the wavelengths from the remaining color set. Left and rightimage perspective data is displayed on alternating rows or columns basedon the orientation of the strip filter elements. Accordingly, theresulting image may appear to have increased resolution because theimage data appears in every row even though the pattern repeats on everyother row.

Step 640 may be performed in a similar manner to step 630 as applied toa second color-coded image perspective.

FIG. 7 shows a block diagram illustrating an exemplary full-colortwo-dimensional or three-dimensional display system 700. System 700 mayinclude, among other features, backlight 720, light guide 130, color ormonochrome liquid crystal display (LCD) panel 140, bus 160, andcontroller 170.

In certain embodiments, display device 710 may be adapted to outputinformation coded as full-color anaglyph three-dimensional imagery.Information may include one or a combination of images, text, video, orthe like. In some embodiments, display device 710 may output imageryusing, among other components, one or a combination of flat paneltechnologies, such as plasma, liquid crystal and light-emitting diode.In certain embodiments, display device 710 may also output imageryusing, among other components, micro display technologies, such asLiquid Crystal on Silicon (LCoS), electro-optic modulators, andmicro-electromechanical systems. For example, other examples, displaydevice 710 may be a system that includes a projector and a screenwherein the color panel is in the projector. Display device 710 may beused in conjunction with viewing device 180 adapted to view imagerygenerated by display device 710.

Backlight 720 may be a light source configured to output one or morecoded image perspectives of a three-dimensional image. For example,backlight 720 may be configured to utilize any one of several colormodels sufficient to reproduce a color spectrum to support full-coloranaglyph three-dimensional imagery or pseudo color multi-spectral imagefusion. For example, in some embodiments, backlight 720 may be adaptedto use an additive color model, such as RGB. Using the RGB color model,varying intensities and bandwidths of red, green, and blue light sourcesmay be combined to produce a broad color spectrum. Backlight 720 mayinclude red LEDs, green LEDs, and blue LEDs. In other embodiments,backlight 720 may be adapted to utilize alternative color models, suchas a four color space or a six color space model. Accordingly, in someembodiments, backlight 720 may include one or a combination ofdifferently colored LEDs, including combinations of greater than andless than three colors.

In some embodiments, backlight 720 may include LEDs grouped as a colorset, each color set configured to produce a particular color spectrum.The color spectrum of the color set may correspond to a portion of thevisible light spectrum used to code an individual image perspective(left or right) of a three-dimensional image. That is, one set of LEDscorresponding to a first color set may be configured to display only oneof the two image perspectives. Similarly, the remaining LEDscorresponding to a second color set may be configured to only displaythe other image perspective. An individual image perspective may beassociated with either a left-eye image or a right-eye image. Right eyefilter 180-A and left eye filter 180-B may be configured to receiveimage data on separate optical channels differentiated based onwavelengths corresponding to each color set. For example, one opticalchannel may be configured to carry information coded based on left-eyeimage perspective and the other optical channel may be configured tocarry information coded based on the right-eye image perspective. Thatis, each color set may be associated with an optical channel to transmitand receive a particular image perspective.

In some embodiments, the transmission range of the color set may bedetermined based on the wavelengths associated with the LEDs comprisingthe color set. For example, backlight 720 may include a first color setcomprised of red LED R₁, green LED G₁, and blue LED B₁. Backlight 720may also include a second color set comprised of red LED R₂, green G₂,and blue LED B₂, each LED having a different wavelength compared thecorresponding LED in the first color set. Thus, a first color set maycorrespond to color spectrum, or color space, used to code either aright-eye or left-eye image perspective of three-dimensional image.Similarly, the second color set may correspond to the remaining imageperspective. In some embodiments, backlight 720 may include other colorsets with at least one red LED, one green LED, and one blue LED. Forexample, a first color set may include red LED R₁, green LED G₂, andblue LED B₁. Similarly, a second color set may include red LED R₂, greenLED G₁, and blue LED B₂.

A particular color space reproduced using a corresponding color set maybe a subset of the visible light spectrum. That is, colors used to codeand to display a particular image perspective may be reproduced to theextent that those colors are reproducible using the combination ofcolors included in the corresponding color set in backlight 720. Incertain embodiments, backlight 720 may comprise color sets that includefour or greater distinct LED colors in each color set to increase thereproducible subset of the visible light spectrum. For example, onecolor set may include a cyan LED in addition to a red, green, and blueLED. The complementary color set may include the same color LEDs, yeteach color may differ slightly in wavelength as previously discussed.Alternatively, the complementary color set may contain base color LEDs,red, green, and blue, adding a yellow LED.

In some applications, additional color LEDs, beyond the base color red,green, and blue LEDs, may be used to display multi-spectral imagery on asingle display panel. For example, a right-eye image perspective may becoded using a red, a green, and a blue LED from a first color set.Similarly, a left-eye image perspective may be coded using differentred, green, and blue LEDs from a complementary color set. A yellow LEDassociated with either the first color or the second color set may becoded to display pseudo color spectral imagery, such as thermal imagery,separately or in combination with the right and the left imageperspectives. Pseudo color spectral imagery may be displayed in varyinghues, or shades, of a single color. For example, a pixel coded witheight bits of information can represent a larger range of colors than arepresentation in the same color space that uses six bits ofinformation. Accordingly, a single color may be reproduced in varyingshades based on the associated pixel resolution. LEDs with sufficientlynarrow bandwidth obviate the need for color filtering. As a result, ahigher proportion of the light emitted leaves display device 710 andcontributes to the image viewed. The system can therefore be more energyefficient and less expensive to manufacture than systems that employ acolor filter.

Light guide 130 may include an optical component adapted to evenlydistribute light from backlight 720 across LCD panel 140. For example,light guide 130 may be optically coupled to backlight 720 using one or acombination of a mixing light guide (not shown) and a mirror (notshown). Light guide 130 may be composed of glass, acrylic, or otherpolymethacrylate material, suitable to couple light from backlight 720to LCD panel 140. Light guide 130 may include an extraction pattern onone surface adapted to provide uniform coupling of light output frombacklight 720 to LCD panel 140. The extraction pattern may be createdusing several methods, including but not limited to, screen printing andinjection molding.

LCD panel 140 may be coupled to receive light from backlight 720 throughlight guide 130. Each liquid crystal light valve may be coupled totransmit light from backlight 720.

In some embodiments, controller 170 may be coupled to communicate withbacklight 720 and LCD panel 140 using bus 160. Bus 160 may include anoptical or electrical communication channel configured to transfer databetween backlight 720, LCD panel 140, and controller 170. In someembodiments, data may include display data received from an externalsource (not shown).

In certain embodiments, display device 710 may be adapted to outputinformation as two-dimensional imagery. In some embodiments, the sixcolor bands (i.e., R₁, R₂, G₁, G₂, B₁, and B₂) could be used to providehigher definition color resolution. In these embodiments, six LEDsrepresenting each of the six color bands correspond to one image pixel.In these embodiments, rather than being limited to blending red, green,and blue, display 710 can blend a broader combination of colors with aresulting increase in available color space. For example, theseembodiments could cross blend from a pallet of two different shades ofred, two different shades of green, and two different shades of blue.

In other embodiments, the six color bands could be used to providehigher spatial resolution. For example, three LEDs representing each ofthe three color bands of a first color set can correspond to one imagepixel, while three LEDs representing each of the three color bands of asecond color set can correspond to another image pixel. In theseembodiments, image resolution is effectively doubled while stillproviding a complete RGB color space.

FIG. 8 illustrates a graph 800 of the spectral transmission of exemplarycolor sets. Color set A may represent a first set of spectral peaks 820,830, and 840 of LEDs associated with a first color set of backlight 720.For example, a first blue LED may have a spectral peak of 432 nm 820. Afirst green LED may have a spectral peak of 518 nm 830. A first red LEDmay have a spectral peak of 615 nm 840. Color set B may represent asecond color set of spectral peaks 821, 831, and 841 of LEDs associatedwith a second color set of backlight 720. For example, a second blue LEDmay have a spectral peak of 466 nm 821. A second green LED may have aspectral peak of 532 nm 831. A second red LED may have a spectral peakof 629 nm 841. As shown in combined spectral transmission graph 800,color set A and color B may represent separate optical channels ofcommon colors shifted in wavelength.

In certain embodiments where display 710 is adapted to displayinformation as two-dimensional imagery, the six color bands 820-841 canbe combined in various ways depending on whether improved colorresolution or improved spatial resolution is desired. In embodimentswhere improved color resolution is desired, six LEDs representing eachof the six color bands correspond to one image pixel. That is, one imagepixel will correspond to six LEDs emitting color bands 820, 821, 830,831, 840, and 841, respectively. In embodiments where improved spatialresolution is desired, three LEDs representing the three color bands ofa color set will correspond to one image pixel. For example, a firstimage pixel will consist of three LEDs emitting color bands 820, 830,and 840, respectively. Similarly, a second image pixel will consist ofthree LEDs emitting color bands 821, 831, and 841 of color set B,respectively. In other embodiments, a pixel can correspond to three LEDshaving color bands representing combinations of peaks 820 and 821, 830and 831, and 840 and 841, respectively.

Other embodiments of the present invention will be apparent to thoseskilled in the art from consideration of the specification and practiceof one or more embodiments of the invention disclosed herein. It isintended that the specification and examples be considered as exemplaryonly, with a true scope and spirit of the invention being indicated bythe following claims.

What is claimed is:
 1. A display apparatus with modes for displayingtwo-dimensional or three-dimensional imagery, the apparatus comprising:a controller; a bus; a liquid crystal display; a light guide; and abacklight comprising LEDs defining a first color set and a second colorset, wherein, when in a three-dimensional display mode, the LEDsdefining the first color set correspond to a first color-coded imageperspective, and the LEDs defining the second color set correspond to asecond color-coded image perspective, and wherein, when in atwo-dimensional display mode, the LEDs defining the first color set andthe second color set correspond to a single image perspective.
 2. Thedisplay apparatus of claim 1, wherein the first color set includeswavelengths corresponding to each of a first red LED, a first green LED,and a first blue LED.
 3. The display apparatus of claim 2, wherein thesecond color set includes wavelengths corresponding to each of a secondred LED, a second green LED, and a second blue LED.
 4. The displayapparatus of claim 3, wherein the first color set is different from thesecond color set.
 5. The display apparatus of claim 1, wherein, in thethree-dimensional display mode, the first color-coded image perspectiveand the second color-coded image perspective correspond to a right-eyeimage and a left-eye image, respectively.
 6. The display apparatus ofclaim 4, wherein, in the two-dimensional display mode, the first redLED, the first green LED, and the first blue LED correspond to a firstimage pixel, and the second red LED, the second green LED, and thesecond blue LED correspond to a second image pixel.
 7. The displayapparatus of claim 4, wherein, in the two-dimensional display mode, thefirst red LED, the first green LED, the first blue LED, the second redLED, the second green LED, and the second blue LED correspond to a firstimage pixel.
 8. The display apparatus of claim 1, wherein the LEDs ofeach color set are distributed in an interleaved pattern.
 9. The displayapparatus of claim 1, wherein the LEDs of each color set are distributedin a pseudo random pattern.